From 9391b7c2342df0efec560578a0b85307b84e7ef6 Mon Sep 17 00:00:00 2001
From: Alexander Medvednikov <alexander@medvednikov.com>
Date: Tue, 12 Aug 2025 01:37:32 +0300
Subject: [PATCH] vls: improve and simplify autocomplete; remove the scanner
 hack

---
 vlib/v/checker/autocomplete.v | 42 ++++++++++++++++++++++++++---------
 vlib/v/checker/checker.v      |  5 +++--
 vlib/v/parser/parser.v        |  7 ++++++
 vlib/v/parser/struct.v        | 10 +++++++++
 vlib/v/pref/line_info.v       | 22 +++++-------------
 vlib/v/pref/pref.v            |  7 +++---
 vlib/v/scanner/scanner.v      |  9 +-------
 vlib/v/token/token.v          |  4 ++++
 vlib/v/token/token_test.v     | 20 +++++++++++++++++
 9 files changed, 86 insertions(+), 40 deletions(-)
 create mode 100644 vlib/v/token/token_test.v

diff --git a/vlib/v/checker/autocomplete.v b/vlib/v/checker/autocomplete.v
index 0b02059af3..11a7bc9db0 100644
--- a/vlib/v/checker/autocomplete.v
+++ b/vlib/v/checker/autocomplete.v
@@ -11,19 +11,31 @@ struct ACFieldMethod {
 	typ  string
 }
 
+fn abs(a int) int {
+	if a < 0 {
+		return -a
+	}
+	return a
+}
+
 fn (mut c Checker) ident_autocomplete(node ast.Ident) {
 	// Mini LS hack (v -line-info "a.v:16")
-	println(
-		'checker.ident() info.line_nr=${c.pref.linfo.line_nr} node.line_nr=${node.pos.line_nr} ' +
-		' pwd="${os.getwd()}" file="${c.file.path}", ' +
-		' pref.linfo.path="${c.pref.linfo.path}" node.name="${node.name}" expr="${c.pref.linfo.expr}"')
+	if c.pref.is_verbose {
+		println(
+			'checker.ident_autocomplete() info.line_nr=${c.pref.linfo.line_nr} node.line_nr=${node.pos.line_nr} ' +
+			' node.col=${node.pos.col} pwd="${os.getwd()}" file="${c.file.path}", ' +
+			//' pref.linfo.path="${c.pref.linfo.path}" node.name="${node.name}" expr="${c.pref.linfo.expr}"')
+		 ' pref.linfo.path="${c.pref.linfo.path}" node.name="${node.name}" col="${c.pref.linfo.col}"')
+	}
 	// Make sure this ident is on the same line as requeste, in the same file, and has the same name
 	same_line := node.pos.line_nr in [c.pref.linfo.line_nr - 1, c.pref.linfo.line_nr + 1, c.pref.linfo.line_nr]
 	if !same_line {
 		return
 	}
-	same_name := c.pref.linfo.expr == node.name
-	if !same_name {
+	// same_name := c.pref.linfo.expr == node.name
+	same_col := abs(c.pref.linfo.col - node.pos.col) < 3
+	// if !same_name {
+	if !same_col {
 		return
 	}
 	abs_path := os.join_path(os.getwd(), c.file.path)
@@ -39,9 +51,14 @@ fn (mut c Checker) ident_autocomplete(node ast.Ident) {
 	sym := c.table.sym(c.unwrap_generic(node.obj.typ))
 	// sb.writeln('VAR ${node.name}:${sym.name} ${node.pos.line_nr}')
 	nt := '${node.name}:${sym.name}'
+	sb.writeln('{')
 	if !c.pref.linfo.vars_printed[nt] { // avoid dups
-		sb.writeln('===')
-		sb.writeln('VAR ${nt}') //${node.name}:${sym.name}')
+		// sb.writeln('===')
+		// sb.writeln('VAR ${nt}') //${node.name}:${sym.name}')
+		sb.writeln('\t"name":"${node.name}",')
+		sb.writeln('\t"type":"${sym.name}",')
+		sb.writeln('\t"fields":[')
+
 		// print_backtrace()
 		/*
 		if sym.kind == .alias {
@@ -75,9 +92,14 @@ fn (mut c Checker) ident_autocomplete(node ast.Ident) {
 			fields << ACFieldMethod{build_method_summary(method), method_ret_type.name}
 		}
 		fields.sort(a.name < b.name)
-		for field in fields {
-			sb.writeln('${field.name}:${field.typ}')
+		for i, field in fields {
+			// sb.writeln('${field.name}:${field.typ}')
+			sb.write_string('\t\t"${field.name}:${field.typ}"')
+			if i < fields.len - 1 {
+				sb.writeln(', ')
+			}
 		}
+		sb.writeln('\n\t]\n}')
 		res := sb.str().trim_space()
 		if res != '' {
 			println(res)
diff --git a/vlib/v/checker/checker.v b/vlib/v/checker/checker.v
index 6fd133e4f0..a3a252e460 100644
--- a/vlib/v/checker/checker.v
+++ b/vlib/v/checker/checker.v
@@ -430,12 +430,13 @@ pub fn (mut c Checker) check_files(ast_files []&ast.File) {
 	// After the main checker run, run the line info check, print line info, and exit (if it's present)
 	if !c.pref.linfo.is_running && c.pref.line_info != '' { //'' && c.pref.linfo.line_nr == 0 {
 		// c.do_line_info(c.pref.line_info, ast_files)
-		println('setting is_running=true,  pref.path=${c.pref.linfo.path} curdir' + os.getwd())
+		// println('setting is_running=true,  pref.path=${c.pref.linfo.path} curdir' + os.getwd())
 		c.pref.linfo.is_running = true
+		// println('linfo path=${c.pref.linfo.path}')
 		for i, file in ast_files {
 			// println(file.path)
 			if file.path == c.pref.linfo.path {
-				println('running c.check_files')
+				// println('running c.check_files')
 				c.check_files([ast_files[i]])
 				exit(0)
 			} else if file.path.starts_with('./') {
diff --git a/vlib/v/parser/parser.v b/vlib/v/parser/parser.v
index d033884901..3902521a1c 100644
--- a/vlib/v/parser/parser.v
+++ b/vlib/v/parser/parser.v
@@ -2635,6 +2635,13 @@ fn (mut p Parser) type_decl() ast.TypeDecl {
 	if p.disallow_declarations_in_script_mode() {
 		return ast.SumTypeDecl{}
 	}
+	if p.is_vls && p.tok.is_key() {
+		// End parsing after `type ` in vls mode to avoid lots of junk errors
+		// If next token is a key, the type wasn't finished
+		p.error('expecting type name')
+		p.should_abort = true
+		return ast.AliasTypeDecl{}
+	}
 	mut name := p.check_name()
 	mut language := ast.Language.v
 	if name.len == 1 && name[0].is_capital() {
diff --git a/vlib/v/parser/struct.v b/vlib/v/parser/struct.v
index 553e4f2d2b..819e1e5154 100644
--- a/vlib/v/parser/struct.v
+++ b/vlib/v/parser/struct.v
@@ -125,6 +125,16 @@ fn (mut p Parser) struct_decl(is_anon bool) ast.StructDecl {
 			}
 		}
 		p.check(.lcbr)
+		// if p.is_vls && p.tok.kind == .key_struct { // p.tok.is_key() {
+		if p.is_vls && p.tok.is_key() {
+			// End parsing after `struct Foo {` in vls mode to avoid lots of junk errors
+			// If next token after { is a key, the struct wasn't finished
+			p.error('expected `}` to finish a struct definition')
+			p.should_abort = true
+			return ast.StructDecl{
+				name: name
+			}
+		}
 		pre_comments << p.eat_comments()
 		mut i := 0
 		for p.tok.kind != .rcbr {
diff --git a/vlib/v/pref/line_info.v b/vlib/v/pref/line_info.v
index 8139e325d8..88d7b16b05 100644
--- a/vlib/v/pref/line_info.v
+++ b/vlib/v/pref/line_info.v
@@ -4,7 +4,7 @@ module pref
 
 fn (mut p Preferences) parse_line_info(line string) {
 	// println("parse_line_info '${line}'")
-	format_err := 'wrong format, use `-line-info "file.v:24:expr_to_look_up"'
+	format_err := 'wrong format, use `-line-info "file.v:24:7"'
 	vals := line.split(':')
 	if vals.len != 3 {
 		eprintln(format_err)
@@ -12,7 +12,8 @@ fn (mut p Preferences) parse_line_info(line string) {
 	}
 	file_name := vals[0]
 	line_nr := vals[1].int() - 1
-	expr := vals[2]
+	col := vals[2].int() - 1
+	// expr := vals[2]
 	if !file_name.ends_with('.v') || line_nr == -1 {
 		eprintln(format_err)
 		return
@@ -20,20 +21,7 @@ fn (mut p Preferences) parse_line_info(line string) {
 	p.linfo = LineInfo{
 		line_nr: line_nr
 		path:    file_name
-		expr:    expr
+		// expr:    expr
+		col: col
 	}
 }
-
-pub fn add_line_info_expr_to_program_text(raw_text string, linfo LineInfo) string {
-	lines := raw_text.split('\n')
-	lines_before := lines[..linfo.line_nr].join('\n')
-	mut expr := linfo.expr
-	if !expr.contains('.') {
-		// Single variable, `foo` => `foo.xx`
-		// expr += '.xxx'
-		// expr = '_ = ' + expr
-		expr = 'println(' + expr + ')'
-	}
-	lines_after := lines[linfo.line_nr..].join('\n')
-	return lines_before + '\n' + expr + '\n' + lines_after
-}
diff --git a/vlib/v/pref/pref.v b/vlib/v/pref/pref.v
index ad0a627644..1d2dbd9385 100644
--- a/vlib/v/pref/pref.v
+++ b/vlib/v/pref/pref.v
@@ -264,9 +264,10 @@ pub mut:
 
 pub struct LineInfo {
 pub mut:
-	line_nr      int             // a quick single file run when called with v -line-info (contains line nr to inspect)
-	path         string          // same, but stores the path being parsed
-	expr         string          // "foo" or "foo.bar" V code (expression) which needs autocomplete
+	line_nr int    // a quick single file run when called with v -line-info (contains line nr to inspect)
+	path    string // same, but stores the path being parsed
+	// expr         string          // "foo" or "foo.bar" V code (expression) which needs autocomplete
+	col          int
 	is_running   bool            // so that line info is fetched only on the second checker run
 	vars_printed map[string]bool // to avoid dups
 }
diff --git a/vlib/v/scanner/scanner.v b/vlib/v/scanner/scanner.v
index 03a3acecb8..b4d6215259 100644
--- a/vlib/v/scanner/scanner.v
+++ b/vlib/v/scanner/scanner.v
@@ -111,14 +111,7 @@ pub fn new_scanner_file(file_path string, comments_mode CommentsMode, pref_ &pre
 	if !os.is_file(file_path) {
 		return error('${file_path} is not a .v file')
 	}
-	mut raw_text := util.read_file(file_path) or { return err }
-	if pref_.line_info != '' {
-		// Add line info expr to the scanner text
-		abs_path := os.join_path(os.getwd(), file_path)
-		if pref_.linfo.path in [file_path, abs_path] {
-			raw_text = pref.add_line_info_expr_to_program_text(raw_text, pref_.linfo)
-		}
-	}
+	raw_text := util.read_file(file_path) or { return err }
 	mut s := &Scanner{
 		pref:                        pref_
 		text:                        raw_text
diff --git a/vlib/v/token/token.v b/vlib/v/token/token.v
index 41576b1627..386d874cd6 100644
--- a/vlib/v/token/token.v
+++ b/vlib/v/token/token.v
@@ -390,6 +390,10 @@ pub fn (t Token) is_next_to(pre_token Token) bool {
 	return t.pos - pre_token.pos == pre_token.len
 }
 
+pub fn (t Token) is_key() bool {
+	return int(t.kind) > int(Kind.keyword_beg) && int(t.kind) < int(Kind.keyword_end)
+}
+
 pub fn (t Token) str() string {
 	mut s := t.kind.str()
 	if s.len == 0 {
diff --git a/vlib/v/token/token_test.v b/vlib/v/token/token_test.v
new file mode 100644
index 0000000000..e99b0e38eb
--- /dev/null
+++ b/vlib/v/token/token_test.v
@@ -0,0 +1,20 @@
+// Copyright (c) 2019-2024 Alexander Medvednikov. All rights reserved.
+// Use of this source code is governed by an MIT license
+// that can be found in the LICENSE file.
+module token
+
+fn test_is_key() {
+	// Test that tokens with keyword kinds return true.
+	assert Token{
+		kind: .key_as
+	}.is_key()
+	assert Token{
+		kind: .key_fn
+	}.is_key()
+	assert Token{
+		kind: .key_mut
+	}.is_key()
+	assert !Token{
+		kind: .name
+	}.is_key()
+}